Rubella embryopathy may not be clinically evident at birth because of covert symptoms, progressive abnormality, or the normal delay in expression of certain functions, such as speech. In 1968, we treated a child with autism whose mother had rubella during the first trimester. The patient was not considered to have had the congenital rubella syndrome. Subsequently, others1,2 described autism, and other behavioral disorders in children with documented prenatal rubella infection. These observations led us to ask whether evidence for prenatal rubella could be obtained in a sample of autistic children, under the age of 6 years, without overt signs of this infection.